TB-500 — Canada Research Brief
TB-500 is a synthetic acetylated heptapeptide corresponding to the active fragment (residues 17–23) of thymosin β4, studied preclinically for actin binding, angiogenesis, and wound repair.
Key facts
| Canonical name | TB-500 |
|---|---|
| Alternate names | Thymosin beta-4 fragment 17-23, Ac-LKKTETQ, Tβ4 active fragment |
| Drug class | Synthetic thymosin β4 fragment (actin-binding research peptide) |
| CAS number | 77591-33-4 |
| Molecular formula | C39H67N11O14 |
| Molecular weight | 889.98 g/mol |
| Sequence | Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln |
Structure and origin
TB-500 is the seven-residue actin-binding motif of thymosin β4, identified by Van Troys et al. (EMBO J 1996) through peptide mapping of the full-length Tβ4 molecule. The fragment retains much of Tβ4's cellular activity in in-vitro assays while being far easier to synthesise and dissolve — which is why commercial research-peptide inventories usually sell "TB-500" rather than full-length thymosin β4.
Preclinical pathways
Preclinical research on TB-500 and its parent Tβ4 converges on three pathways:
- Actin sequestering and cell migration. Both molecules bind G-actin monomers and modulate the pool available for filament assembly — the mechanism for their reported effects on cell motility and tissue remodelling.
- Angiogenesis. In rodent wound and cardiac injury models (Bock- Marquette et al., Nature 2004), Tβ4 treatment promoted new blood-vessel formation.
- Anti-inflammatory signalling. Tβ4 has been linked to modulation of NF-κB in multiple in-vitro systems, with effects on cytokine profiles downstream.
Note that most published evidence for these pathways uses full-length Tβ4. TB-500 is assumed to retain the actin-binding activity but not necessarily all of the non-actin-related effects.
Comparisons
- BPC-157 vs TB-500 — pathway and evidence quality differences.
Storage
Store lyophilised TB-500 at −20°C. Reconstituted peptide is stable refrigerated at 2–8°C for approximately 2–4 weeks.
Frequently asked questions
What is TB-500?
Is TB-500 the same as thymosin β4?
How does TB-500 differ from BPC-157?
What is TB-500's molecular weight?
References
- [1]Van Troys M, Dewitte D, Goethals M, et al.. The actin-binding site of thymosin beta 4. EMBO Journal, 1996. PMID: 8610111
- [2]Bock-Marquette I, Saxena A, White MD, et al.. Thymosin β4 and cardiac repair. Nature, 2004. PMID: 15306811
- [3]National Center for Biotechnology Information. PubChem CID 16132341 — TB-500 fragment, 2024